Rigid polyurethane foams and polyesters for use therein



United States Patent Oifice 3,399,154 Patented Aug. 2'7, 1968 3,399,154RIGID POLYURETHANE FOAMS AND POLY- ESTERS FOR USE THEREIN CarlBernstein, Deerfield, and Kermit Longley, Park Forest, Ill., assignorsto Witco Chemical Company, Inc., New York, N.Y., a corporation ofDelaware N Drawing. Original application Oct. 22, 1965, Ser. No.502,516, now Patent No. 3,298,974, dated Jan. 17, 1967. Divided and thisapplication Jan. 16, 1967, Ser. No.

7 Claims. (Cl. 26022) ABSTRACT OF THE DISCLOSURE This is a division ofapplication Ser. No. 502,516, filed Oct. 22, 1965, now US. Patent No.3,298,974, issued Jan. 17, 1967, and a continuation-in-part ofapplication Ser. No. 274,855, filed Apr. 22, 1963, which is acontinuation-in-part of application Ser. No. 808,315, filed Apr. 23,1959, both of said applications having been abandoned.

Polyesters used in the production of rigid foams are described innumerous patents and publications illustrative of which are US. PatentsNos. 2,806,835, 2,806,836, 2,811,493, 2,836,575 and 2,846,408. The usualpolyesters are made by reacting a dicarboxylic acid preferably adipicacid, and a trio] such as trimethylolpropane (TMP). A variant formcomprises replacing about by weight of the adipic acid with phthalicanhydride. Since phthalic anhydride is materially cheaper than adipicacid; and since polyesters utilizing phthalic anhydride exhibit betterprop erties, particularly when foamed with fluorohydrocarbon inert gasessuch as Freon 11, Genetrol 11, and Isotron 11 (as described, forinstance, in Republic of South Africa Patent No. 3,329/56), since theresulting foams retain such gases for longer periods of time than whereadipic acid alone is used in the production of the polyesters, it ishighly desirable to be able to employ as much phthalic anhydride aspossible in the preparation of the polyesters. Unfortunately, however,when adipic acid is replaced by phthalic anhydride, the resultingpolyesters are considerably more viscous than in the case where adipicacid is utilized as the polycarboxylic acid constituent of thepolyesters. While efforts have heretofore been made, therefore, toattempt to utilize as much phthalic anhydride as possible in place ofadipic acid, in general, only very minor proportions of phthalicanhydride, generally not more than about 25% by weight of the mixture.of adipic acid and phthalic anhydride, can be utilized with reasonablesatisfaction for the production of the polyesters used for themanufacture of rigid foams. It has also heretofore been proposed, asshown in U.S. Patent No. 3,138,562, to produce cellular polyurethaneplastics comprising rigid foams utilizing polyesters made by reactingtogether (1) aliphatic polyhydric alcohols (such as trimethylolpropane),(2) polycarboxylic acids or mixtures thereof (such as adipic acid andphthalic anhydride), (3) long chain unsaturated fatty acids (such as.oleic acid), and (4) polyhydric polyalkylene ethers having a molecularweight of at least about 400 and in which at least about 50% of thealkylene radicals contain at least 3 carbon atoms (such as variouspropoxylated trimethylol propanes). Such polyesters are radicallydifferent from the polyesters utilized pursuant to our invention, thepolyesters of said Patent No. 3,138,562 using large proportions of freepolyhydric alcohols in the polyester esterification and beingcharacterized in that the adducts which are utilized have very lowcontents of hydroxyl groups (of the order of 1 to 4 mini-equivalents,per gram, of hydroxyl groups) and in that the adducts require thepresence of at least 50% of the alkylene radicals being in the form ofalkylene radicals containing at least 3 carbon atoms. Moreover, thecompressive strengths of the foams produced pursuant to disclosures ofsaid patent are, generally, materially less than the compressivestrengths of rigid foams produceable in accordance with our presentinvention.

The problems involved in the production of satisfactory polyesters forutilization in the manufacture of rigid foams are of multiple character.Not only is there the aspect of cost involved but, also, there areproblems relating to viscosities, good water resistance, and goodretention of the gases which are utilized in the production of thefoams, particularly the inert fluorohydrocarbons. To attempt to meet theproblems, various approaches have been sug gested. Certain of them haveinvolved the production of polyethers. Various of the polyether-typematerials, although producing rigid foams, commonly produce foams whichare friable unless cured at elevated temperatures for a short time or atroom temperature for extended periods. In any event, no adequatelysatisfactory solution has been found to meet the several problemsinvolved.

The present invention is based on the discovery of new and highly usefulpolyesters which are very inexpensive to manufacture, and on theproduction of rigid polyurethane foams utilizing said polyesters, saidfoams having highly satisfactory properties for the uses to which suchfoams are conventionally placed, as, for instance, as insulatingmaterials in the refrigeration industry. The polyesters, made inaccordance with our invention, can utilize phthalic anhydride entirelyas the dicarboxylic acid reactant or, if desired, upwards of 25% of thetotal dicarboxylic acid utilized in the production of the polyesters canbe phthalic anhydride. Furthermore, in certain broader aspects of theinvention, no phthalic anhydride need be utilized and polyesters areobtained with other dicarboxylic acids which possess highly advantageousproperties, particularly for use in the production of rigid polyurethanefoams. In a still further aspect of our invention, novel esters orpolyesters are produced wherein no dicarboxylic acid or polycarboxylicacid is utilized, and such esters or polyesters are usable to produceexcellent rigid polyurethane foams.

In order to achieve the advantageous results of the present invention,it has been found, among other things, that there should be used, in theproduction of the esters or polyesters of the present invention, anethylene oxide adduct of an aliphatic polyhydric alcohol having at leastthree hydroxy groups and, more particularly, an aliphatic polyhydricalcohol having from 4 to 6 hydroxy groups, the ethylene oxide content ofsaid adduct being controlled so as to lie Within certain ranges as setforth below. More specifically, we have found that the ethylene oxideadduct of the polyol must be of such character that, for each mol ofsaid polyol, which in the usual case will be an-aliphatic polyhydricalcohol containing from 3 to 6 carbon atoms, such a number of mols ofethylene oxide is reacted therewith as to produce an adduct whichcontains from 10 to 22 mini-equivalents, per gram, of hydroxyl groups.In addition, we have found that, in order to achieve the best results inaccordance with our invention, said polyesters should have certainhydroxyl numbers. Thus, where the polyesters are produced from theaforesaid adducts by esterification with dicarboxylic acids alone (orwith dicarboxylic acids containing minor amounts of tricarboxylic orhigher polycarboxylic acids), as described below, the hydroxyl numbersshould lie between 280 and 550 and, more particularly, in the range of320 to 500. Where the polyesters are produced from the aforesaid adductsby esterification with mixtures of dicarboxylic acids (or withdicarboxylic acids containing minor amounts of tricarboxylic acids orhigher polycarboxylic acids) and water-immiscible higher molecularweight monocarboxylic or fatty acids, as described below, the hydroxylnumbers should lie between 400 and 600 and, more particularly, in therange of 450 to 500. Where the esters or polyesters are produced fromthe aforesaid adducts by esterification with water-immiscible highermolecular weight monocarboxylic or fatty acids and little or nodicarboxylic or other polycarboxylic acids, as described below thehydroxyl numbers should lie between 500 and 800 and, more particularly,in the range of 600 to 700.

Various aliphatic polyhydric alcohols or polyols, or mixtures of any twoor more thereof, containing at least 3 hydroxyl groups, can be utilizedas the starting material with which the ethylene oxide is reacted toproduce the adducts which are then reacted as pointed out below toproduce the polyesters. Among such aliphatic polyhydric alcohols are,for instance, glycerol, trimethylolpropane, triethylolpropane,trimethylolethane, triethanolamine, hexanetriols, pentaerythritol,dipentaerythritol, polyglycerols such as diglycerol, triglycerol,tetraglycerol and higher polyglycerols and mixtures thereof, sorbitol,mannitol, and the like. It is especially advantageous to use aliphaticpolyhydric alcohols containing from 4 to 6 hydroxyl groups, or mixturesthereof with aliphatic polyhydric alcohols containing 3 hydroxyl groups.

The ethylene oxide content in the adducts of the polyols will varydepending upon the number of hydroxyl groups present in the polyol.Thus, for example, in the case of trimethylolpropane, for each mol ofthe trimethylolpropane the ethylene oxide content of the adduct is fromabout 0.5 mol to not substantially in excess of 3 mols. In the case ofsorbitol, for each mol thereof present in an adduct with ethylene oxide,the number of mols of ethylene oxide will range from about 3 mols toabout 8 mols. The governing criterion in this regard, however, as statedpreviously, is that the adduct contains from 10 to 22 milliequivalents,per gram, of hydroxyl groups. It is particularly preferred that saidadducts be made with ethylene oxide as the sole adducting alkyleneoxide. However, minor proportions of other alkylene oxides can be usedin producing the adducts, such as propylene oxide or butylene oxides.Where used, the mol ratio of the ethylene oxide to the propylene oxideor butylene oxide should be at least 2 to 1 and, more advantageously,said mol ratio should be at least 4 to 1. Generally speaking, the use ofpropylene oxide or butylene oxide in the production of the adductsresults in polyesters with higher viscosities and in rigid polyurethanefoams produced from such polyesters which have a greater tendency toshrinkage. Where propylene oxide or butylene oxide is used in theproduction of the adduct, it may be reacted after or before the ethyleneoxide is adducted with the polyhydric alcohol. Conventional techniquesof adducting polyhydric alcohols with alkylene oxides may be used.

It has been found, surprisingly, among other things, as has beenindicated above, that, when adducts of the character described above areesterified with phthalic anhydride or with mixtures of adipic acid andphthalic anhydride in which the phthalic anhydride content is at least25% of the total of the mixture of adipic acid and phthalic anhydride,polyesters are obtained having unusually relatively low viscosities.Generally speaking, polyesters are readily produced in accordance withthe present invention in which the viscosities, measured in centipoises(cps.) at 25 degrees C., are in the range of 20,000 to 60,000. It ispreferred, for use in the production of rigid polyurethane foams, thatthe viscosities of said polyesters 4 do not exceed 100,000 cps. at 25degrees C., and, more desirably, that they lie in the range of 40,000 to60,000 cps.

In one particularly advantageous aspect of our inven tion (thepolyesters are derived from the esterification of the above-describedadducts with phthalic anhydride alone as the carboxylic acidester-forming constituent, or with phthalic anhydride constituting atleast 25% and, better still, at least 40% of the total of thepolycarboxylic acid utilized in the esterification reaction to producethe polyesters. In one of its broader aspects, our inventioncontemplates the utilization of other aromatic polycarboxylic acid, ormixtures of two or more thereof, in place of or in conjunction Withphthalic anhydride as, for instance, terephthalic acid, isophthalicacid, trimellitic acid, chlorendic anhydride and chlorendic acid, andnaphthalene dicarboxylic acid. It also contemplates the employment, inplace of adipic acid, of other aliphatic polycarboxylic acids which havebeen conventionally used in the production of polyesters for themanufacture of rigid polyurethane foams as disclosed, for instance, invarious of the patents mentioned herein. However, the employment ofadipic acid and dimeric acids such as those sold under the designation3065S (Emery Industries) as the aliphatic polycarboxylic acid, in thoseinstances in which an aliphatic polycarboxylic acid is utilized, isparticularly preferred. In thOse instances in which polycarboxylic acidsare utilized to esterify the aforesaid adducts to produce the polyestersof the present invention, dicarboxylic should constitute at least thesubstantially major polycarboxylic acid constituent. Tricarboxylic acidcan be utilized in distinctly minor proportions but they tend to resultin the production of polyesters with unduly high viscosities and it ispreferred to avoid their use entirely. Where used, they should beemployed in proportions such as not to result in polyesters havingviscosities in excess of 100,000 cps. at 25 degrees C.

As stated above, certain of the novel esters of polyesters of ourpresent invention are made by esterification of the above-describedadducts with dicarboxylic acids in admixture with water-immisciblehigher molecular weight monocarboxylic or fatty acids, or byesterification of said adducts with water-immiscible higher molecularweight monocarboxylic or fatty acids alone. Among such monocarboxylic orfatty acids are lauric acid, myristic acid, palmitic acid, stearic acid,oleic acid, tall oil fatty acids, linoleic acid, ricinoleic acid andmixtures of two or more of such monocarboxylic acids, including suchmixtures as are or may be derived from commercial sources. It isparticularly preferred, so far as this phase of our invention isconcerned, to utilize oleic acid or tall oil fatty acids or similarunsaturated monocarboxylic acids because the saturated monocarboxylicacids tend to produce polyesters with unduly high viscosities. Theutilization of monocarboxylic acids in the production of the esters orpolyesters results, among other things, in esters or polyesters havingincreased solubility in fluorohydrocarbons, such as Freon 11, which isadvantageous in those procedures in which rigid polyurethane foams areproduced where the gas producing agent is a fluorohydrocarbon, since,ordinarily, the fluorohydrocarbons used in such processes are not verysoluble in the polyesters which are conventionally used in producingrigid polyurethane foams. While, as stated above, esters or polyestersof the above-described adducts can be made with the aforementionedmonocarboxylic acids alone, it is desirable to utilize a proportion of adicarboxylic acid together with said monocarboxylc acids since thisresults in a greater rigidity of the rigid polyurethane foams made fromsaid polyesters. The relative proportions of the dicarboxylic acids andthe monocarboxylic acids, where mixtures of both are used, are variablewithin wide limits, the dicarboxylic acid being either appreciablygreater or appreciably less than the monocarboxylic acid on a weightbasis. Thus, for instance, and as will be apparent from the followingexamples, the

monocarboxylic acids, such as oleic acid or tall oil fatty acids, mayconstitute 50% to 150% by weight of the dicarboxylic acid, or thedicarboxylic acid may constitute from 50 to 150% by Weight of themonocarboxylic acid, with lesser or greater relative proportions as maybe desired to obtain certain particular viscosities in the polyesters aswell as various other properties.

The utilization of tall oil fatty acids, oleic acid, and likeunsaturated higher fatty acids, in conjunction with phthalic anhydrideor other dicarboxylic acids, in the production of various of thepolyesters of the present invention, enables polyesters of lowerviscosities to be produced, economics in cost are achieved, andproduction of excellent fine-celled rigid polyurethane foams is obtainedby either the so-called one shot or prepolymer procedures or techniques.

The following examples are illustrative of the production of esters orpolyesters made in accordance with our invention. It will be understoodthat numerous other esters or polyesters can readily be producedfollowing the guidance and teachings disclosed herein without in any waydeparting from the principles of our invention.

EXAMPLE 1 grees C.)

EXAMPLE 2 2 mols of an adduct of 1 mol of TMP with 1.76 mols of ethyleneoxide are esterified, in the manner described in Example 1, with 1 molof phthalic anhydride. The resulting polyester, having an acid number of1.5 and an hydroxyl number of 386, has a comparatively low viscosity,namely, about 100,000 cps. (25 degrees C.).

EXAMPLE 3 2 mols of an adduct of 1 mol of sorbitol with 6 mols ofethylene oxide (said adduct containing about 13.5 milliequivalents, pergram, of hydroxyl groups) are esterified, as described in Example 1,with 0.5 mol of adipic acid and 1 mol of phthalic anhydride.

EXAMPLE 4 2 mols of an adduct of 1 mol of pentaerythritol with 3 mols ofethylene oxide (said adduct containing about milli-equivalents, pergram, of hydroxyl groups) are esterified, as described in Example 1,with 0.5 mol of isophthalic acid and 0.5 mol of adipic acid.

EXAMPLE 5 2 mols of an adduct of 1 mol of trimethylolethane with 2.5mols of ethylene oxide (said adduct containing about 13mini-equivalents, per gram, of hydroxyl groups) are esterified, asdescribed in Example 1, with 0.75 mol of adipic acid and 0.5 mol ofphthalic anhydride.

EXAMPLE 6 1 mol of an adduct of 1 mol of TMP with 1.75 mols of ethyleneoxide (said adduct containing approximately 14 milli-equivalents, pergram, of hydroxyl groups) are esterified with 0.5 mol phthalic anhydrideat a temperature of 225-250 degrees C. in an inert gas atmosphere, Theresulting polyester has an acid number of 1.5 and an hydroxyl number of402.

EXAMPLE 7 1 mol of an adduct of 1 mol of TMP with 1.75 mols of ethyleneoxide are esterified with 0.25 mol adipic acid and 0.25 mol of phthalicanhydride at a temperature of 225- 250 degrees C. in an inert gasatmosphere. The resulting polyester has an acid number of 1.5 and anhydroxyl number of 404.

EXAMPLE 8 1 mol of an adduct of 1 mol of TMP with 1.75 mols of ethyleneoxide are esterified with 0.5 mol isophthalic acid at a temperature of225-250 degrees C. in an inert gas atmosphere. The resulting polyesterhas an acid number of 0.2 and an hydroxyl number of 398.

EXAMPLE 9 1 mol of an adduct of '1 mol of TMP with 2.41 mols of ethyleneoxide (said adduct containing about 12 milliequivalents, per gram, ofhydroxyl groups) are esterified with 0.5 mol of phthalic anhydride at atemperature of 225-250 degrees C. in an inert gas atmosphere. Theresulting polyester has an acid number of 1.6 and an hydroxyl number of365.

EXAMPLE 10 1 mol of an adduct of 1 mol of TMP with 2.41 mols of ethyleneoxide are esterified with 0.59 mol phthalic anhydride at a temperatureof 225-250 degrees C. in an inert gas atmosphere. The resultingpolyester has an acid number of 1.7 and an hydroxyl number of 325.

EXAMPLE ll 1 mol of an adduct of 1 mol of TMP with 1.97 mols of ethyleneoxide (said adduct containing about 13.5 milliequivalents, per gram, ofhydroxyl groups) are esterified with 0.5 mol of phthalic anhydride at atemperature of 225-250 degrees C. in an inert gas atmosphere. Theresulting polyester has an acid number of 1.1 and an bydroxyl number of386.

EXAMPLE 12 1 mol of an adduct of 1 mol of glycerol with 2.07 mols ofethylene oxide (said adduct containing about 16 milliequivalents, pergram, of hydroxyl groups) are esterified with 0.5 mol phthalic anhydrideat a temperature of 225-250 degrees C. in an inert gas atmosphere. Theresulting polyester has an acid number of 1.2 and an hydroxyl number of450.

EXAMPLE 13 252 g. of an adduct of 0.82 mol of TMP, 0.27 mol ofpentaerythritol and 2.42 mols of ethylene oxide are ester ified with 74g. of phthalic anhydride at a temperature of 225-250 degrees C. in aninert gas atmosphere. The resulting polyester has an acid number of 0.6and an hydroxyl number of 435.

EXAMPLE 14 An adduct was prepared from 124 grams of glycerol, 376 gramsof pentaerythritol and 380 grams of ethylene oxide. 440 grams of saidadduct were esterified with a mixture of 163 grams of phthalic anhydrideand 99 grams of tall oil fatty acids at a temperature of 225-250 degreesC. in an inert gas atmosphere until the resulting polyester product hada hydroxyl number of 412 and an acid number of 1.

EXAMPLE 15 440 grams of the adduct used in Example 14 were esterified inthe manner described in Example 14 with a mixture of 133 grams ofphthalic anhydride and grams of tall oil fatty acids until the resultingpolyester product had a hydroxyl number of 421 and an acid number of 2.Its viscosity measured 30,000 cps. at 25 degrees C.

EXAMPLE 16 440 grams of the adduct used in Example 14 were esterified inthe manner described in Example 14 with a mixture of 122 grams ofphthalic anhydride and grams of tall oil fatty acids until the resultingpolyester product had a hydroxyl number of 417 and an acid number of0.5. Its viscosity measured 20,000 c.p.s., at degrees C.

EXAMPLE 17 440 grams of the adduct used in Example 14 were esterified inthe manner described in Example 14 with a mixture of 140 grams ofphthalic anhydride and 70 grams of tall oil fatty acids until theresulting polyester product had a hydroxyl number of 480 and an acidnumber of 1.

EXAMPLE 18 517 grams of the adduct of Example 18 were esterified with 89grams of phthalic anhydride and 114 grams of oleic acid, in the mannerdescribed in Example 18, to produce a polyester having an hydroxylnumber of 466, an acid number of 1, and a viscosity at 25 degrees C. of6,000 c.p.s.

EXAMPLE 20 222 grams of an adduct prepared from 94 grams ofpentaerythritol, 31 grams of glycerol and 97 grams of ethylene oxidewere esterified with 113 grams of olelc acid, in the manner described inExample 18, to produce a polyester having an hydroxyl number of 595 andan acid number of 1.

EXAMPLE 21 258 grams of an adduct prepared from 94 grams ofpentaerythrito,l 31 grams of glycerol and 133 grams of ethylene oxidewere esterified with 70 grams of oleic acid, in the manner described inExample 18, to produce a polyester having an hydroxyl number of 610 andan acid number of 1.

EXAMPLE 22 1 mol of an adduct of 1 mol of TMP with 1.4 mols of ethyleneoxide (said adduct containing approximately 15 mini-equivalents, pergram, of hydroxyl groups) are esterified with 0.25 mol adipic acid and0.25 mol of phthalic anhydride at a temperature of 225250 degrees C. ina nitrogen atmosphere. The resulting polyester has an acid number of 1.5and a hydroxyl number of 408.

In connection with the preparation of rigid polyurethane foams from thepolyesters of this invention, as has previously been indicated it isespecially desirable to produce them by utilization of inert gas formingor propellant techniques such as disclosed, for instance, by theaforementioned South Africa patent. The source materials or propellantsare those halogen-substituted alkanes which are either gaseous or whichare liquids with a boiling point not materially higher than roomtemperature at atmospheric pressure and in all cases lower than thereaction temperature of the polyester-diisocyanate mixture. Thereference in the claims to the utilization of halogensubstituted alkaneswill be understood to mean those halogen-substituted alkanes whichpossess the foregoing properties. They are, per se, known in the art.The said halogen-subsituted alkanes are dissolved in the prepolymer andthe resulting composition is mixed with the polyester, the temperatureof the mixture then being permitted to rise above the boiling point ofthe gas in the mixture whereby to produce the polyurethane foam due tothe expansion of the gas. Furthermore, as disclosed in said patent,carbon dioxide and oxides of nitrogen can be admixed with thehalogen-substituted alkane and polyester. The disclosures of saidpatents, to the extent that they deal with the use ofhalogen-substituted alkanes for effecting foaming, are incorporatedherein by reference. Monochlorodifiuoromethane anddichlordifluoromethane are two of the particularly preferredhalogen-substituted alkanes. While it is particularly advantageous toutilize such foaming technique, it will be understood that the foamingmay also be accomplished by conventional techniques which rely upon thepresence of small amounts of water cooperation with the polyisocyanatesin forming the carbon dioxide gas which produces the foaming.

The esters of the present invention can be foamed by either prepolymeror one shot techniques. These techniques per se are known in the art.The following are typical examples, given solely by way of illustration,of the production of rigid polyurethane foams utilizing certain of thepolyestersmade in accordance with this invention as described above. Itwill be understood that numer' ous other examples will be readilyapparent in the light of the guiding principles and teachings which areprovided herein.

Example A A prepolymer is made by adding 20 parts of the polyester ofExample 6 to parts of tolylene diisocyanate in a flask with goodstirring and the maintenance of a dry atmosphere. The temperature iskept below degrees C. by cooling. After cooling to room temperature, theprepolymer is incorporated into the following formula:

Parts by weight Polyester of Example 6 108 Prepolyrner 100 Silicone X521 (Union Carbide Corp.) 0.5 Dibutyl tin dilaurate (Union Carbide Corp.Stabilizer P 22) 0.3 Freon 11 33 Example B In this example, the one shottechnique is utilized, no prepolymer being employed.

Parts by weight Polyester of Example 9 71 Tolylene diisocyanate 40Silicone X 520 (Union Carbide Corp.) 0.3N,N,N,N-tetramethyl-1,3-butanediamine 0.3 Freon 11 15 The polyester,silicone X 520 and N,N,N,N-tetrarnethyl- 1,3-butanediamine are premixedand there is added thereto a premix of the tolylene diisocyanate andFreon 11. After thorough. mixing for about 30 seconds the mixture ispoured into a mold and allowed to expand. Alternatively, this system canbe foamed as a three component system (polyester premix, tolylenediisocyanate and Freon 11) in a conventional foaming machine.

Example C In this example, the one shot technique is utilized, noprepolymer being employed, the blowing being effected with Freon 11.

Parts by weight Polyester of Example 15 63 Tolylene idiisocyanate 40Silicone X 521 0.25 Dibutyl tin dilaurate 0.15 Freon 11 15 The proceduredescribed in Example B is followed.

Example D In this example, the one shot technique is utilized, noprepolymer being employed, the blowing being effected by carbon dioxide.

Parts by weight The polyester, silicone X 521, dimethylethanolamine andWater are premixed and then the tolylene diisocyanate is added. After 15seconds of thorough mixing, the mixture is poured into a mold andallowed to expand.

The rigid foams produced as described above were nonfriable and hadexcellent properties. Tests thereof made in comparison with a rigid foamproduced from a typical branched chain polyether by placing them in anoven at 67 degrees C. at 100% humidity for several days showed that thefoam made from the commercial branched chain polyether exhibited grossdistortion and a large gain in weight whereas, by way of sharp contrast,the foams made with the polyesters of the present invention exhibitedlittle distortion and only slight gains in weight. The rigid foams madein accordance with our invention also very effectively retained thefluorohydrocarbon.

With respect to the production of the polyurethane foams utilizing thepolyesters of this invention, the organic polyisocyanates, usuallydiisocyanates alone or in admixture with small amounts, of the order ofto or more of triisocyanates, catalysts, stabilizers, coupler,emulsifying agents and the proportions of water (where such is used)utilized in conjunction therewith are per se known in the art. Amongsuch organic polyisocyanates are, for instance, tolylene diisocyanate(in commercial form it is usually a mixture containing about 80% of the2,4-isomer and 20% of the 2,6-isomer), hexamethylene diisocyanate,P-phenylene diisocyanate, triphenylmethyl triisocyanate andbenzene-1,3,5-triisocyanate. Among the catalysts are N-ethyl morpholine,dimethylethanolamine and triethylamine. Among the emulsifying agents,which may be of anionic or nonionic character, may be mentioned ethyleneoxide reaction products with sorbitan esters such as sorbitanmonooleates, sorbitan monostearate and sorbitan monopalmitate; ethyleneoxide reaction products with alkyl phenols; and mixed emulsifiers suchas those sold under the designation Witco 77-86 by Witco ChemicalCompany, Inc. Reference is made to such patents as No. 2,779,689 fordisclosures of other organic diisocyanates, catalysts, emulsifyingagents, proportions of reactants to produce the polyurethane foams, andfor other information generally concerning known techniques of producingthe foams from polyesters. Other patents disclosing methods of producingpolyurethane foams include, for instance, Nos. 2,785,739, 2,787,601,2,788,335, and the foaming techniques disclosed therein can broadly beutilized in forming the rigid polyurethane foams from the novelpolyester compositions of this invention.

The term consisting essentially of as used in the claims in thedefinition of the ingredients employed in the production of polyester isintended to exclude the presence of other materials which wouldinterfere substantially with the properties and characteristics of thepolyesters for the production of rigid polyurethane foams, but isintended not to exclude the presence of other ingredients in minoramounts and of such character as not materially adversely to affect theproperties and characteristics of the polyesters for the production ofrigid polyurethane foams.

What we claim as new and desire to protect by Letters Patent of theUnited States is:

1. A normally liquid polyester having particular utility for thepreparation of rigid polyurethane foams comprising an esterificationreaction product consisting essentially of (a) a mixture of an aromaticdicarboxylic acid component and a water-immiscible higher molecularweight fatty acid, with (b) a member selected from the group of alkyleneoxide adducts consisting of (l) ethylene oxide adducts of aliphaticpolyhydric alcohols and (2) mixed ethylene oxide and propylene orbutylene oxide adducts of aliphatic polyhydric alcohols the mol ratio ofthe ethylene oxide to the propylene or butylene oxide being at least 2to 1, said aliphatic polyhydric alcohols containing at least 3 hydroxygroups, said adduct containing, for each mol of said aliphaticpolyhydricalcohol, such a number of mols of said alkylene oxide wherebysaid adduct contains from 10 to 22 milli-equivalents, per gram, ofhydroxyl groups, said polyester having an hydroxyl number between 400and 600.

2. A normally liquid polyester having particular utility for thepreparation of rigid polyurethane foams comprising an esterificationreaction product consisting essentially of (a) a mixture of adicarboxylic acid component of which phthalic anhydride constitutes atleast 25% by weight and a water-immiscible higher molecular weightunsaturated fatty acid, with (b) a member selected from the group ofalkylene oxide adducts consisting of (1) ethylene oxide adducts ofaliphatic polyhydric alcohols and (2) mixed ethylene oxide and propyleneor butylene oxide adducts of aliphatic polyhydric alcohols the mol ratioof the ethylene oxide to the propylene or butylene oxide being at least4 to 1, said aliphatic polyhydric alcohols containing predominately from4 to 6 hydroxy groups, said adduct containing, for each mol of saidaliphatic polyhydric alcohol, such a number of mols of said alkyleneoxide whereby said adduct contains from 10 to 22 milli-equivalents, pergram, of hydroxyl groups, sadi polyester having an hydroxyl numberbetween 400 and 600.

3. A normally liquid polyester having particular utility for thepreparation of rigid polyurethane foams comprising an esterificationreaction product consisting essentially of (a) a mixture of an aromaticdicarboxylic acid and adipic acid and a member selected from the groupconsisting of oleic acid and tall oil fatty acids, with (b) an ethyleneoxide adduct of an aliphatic polyhydric alco-. hol, said aliphaticpolyhydric alcohol containing from 3 to 6 hydroxy groups, said adductcontaining, for each mol of said aliphatic polyhydric alcohol, such anumber of mols of ethylene oxide whereby said adduct contains from 10 to22 milli-equivalents, per gram, of hydroxyl groups, said polyesterhaving an hydroxyl number between 400 and 600.

4. A normally liquid polyester having particular utility for thepreparation of rigid polyurethane foams comprising an esterificationreaction product consisting essentially of (a) a water-immiscible highermolecular weight fatty acid, with (b) a member selected from the groupof alkylene oxide adducts consisting of (1) ethylene oxide adducts ofaliphatic polyhydric alcohols and (2) mixed ethylene oxide and propyleneor butylene oxide adducts of aliphatic polyhydric alcohols the mol ratioof the ethylene oxide to the propylene or butylene oxide being at least2 to 1, said aliphatic polyhydric alcohols containing .at least 3hydroxyl groups, said adduct containing, for each mol of said aliphaticpolyhydric alcohol, such a number of mols of said alkylene oxide wherebysaid adduct contains from 10 to 22 milli-equivalents, per gram, ofhydroxyl groups, said polyester having an hydroxyl number between 500and 800.

5. A normally liquid polyester having particular utility for thepreparation of rigid polyurethane foams comprising an esterificationreaction product consisting essentially of (a) a water immiscible highermolecular weight unsaturated fatty acid, with (b) a member selected fromthe group of alkylene oxide adducts consisting of (l) ethylene oxideadducts of aliphatic polyhydric alcohols and (2) mixed ethylene oxideand propylene or butylene oxide adducts of aliphatic polyhydric alcoholsthe mol ratio of the ethylene oxide to the propylene or butylene oxidebeing at least 4 to 1, said aliphatic polyhydric alcohols containingpredominately from 4 to 6 hydroxy groups, said adduct containing, foreach mol of said aliphatic polyhydric alcohol, such a number of mols ofsaid alkylene oxide whereby said adduct contains from 10 to 22milli-equivalents, per gram, of hydroxyl groups, said polyester havingan hydroxyl number between 500 and 800.-

6. A normally liquid polyester having particular utility for thepreparation of rigid polyurethane foams comprising an esterificationreaction product consisting essentially of (a) a member selected fromthe group consisting of oleic acid and tall oil fatty acids, with (b) anethylene oxide adduct of an aliphatic polyhydric alcohol, said aliphaticpolyhydric alcohol containing from 3 to 6 hydroxy groups, said adductcontaining, for each mol of said aliphatic polyhydric alcohol, such anumber of mols of ethylene oxide whereby said adduct contains from 10 to22 mini-equivalents, per gram, of hydroxyl groups, said polyester havingan hydroxyl number between 500 and 800.

7. A normally liquid polyester having particular utility for thepreparation of rigid polyurethane foams comprising an esterificationreaction product consisting essentially of (a) a mixture of phthalicanhydride and a lesser amount, by weight, of a member selected from thegroup consisting of oleic acid and tall oil fatty acids, with anethylene oxide adduct of a mixture of pentaerythritol and glycerol inwhich the amount of pentaerythritol is approximately three times that ofthe glycerol, by weight, said adduct containing, for each rnol of saidmixture of pentaerythritol and glycerol, such a number of mols ofethylene oxide whereby said adduct contains from 10 to 22milli-equivalents, per gram, of hydroxyl groups, said polyester havingan hydroxyl number between 400 and 500, and an acid number between 1.5and 2.

References Cited UNITED STATES PATENTS 3,062,671 11/1962 Kaupp et a12604l0.6 3,110,736 11/1963 De Groote et al. 2604l0.6 3,138,562 6/1964Nischk et al 26O--2.5 3,325,547 6/1967 Cour et a1. 26075 3,340,2959/1967 Wheeler et al. 2604l0.6

DONALD E. CZAJA, Primary Examiner.

R. W. GRIFFIN, Assistant Examiner.

